Based on a newly developed cytogenetic method which yields results in a high percentage of bladder cancers (more than 70%) and utilizing other approaches, we wish to extend our studies on the cytogenetic aspects of bladder cancer to a larger series of patients in order to expand our previously obtained observations on the significance of marker chromosomes in bladder cancer recurrence and the possible relationship of nonrandom changes (for example, lp- and involvement of chromosome #8) to its causation. The chromosome changes will be correlated with clinical, pathologic and therapeutic aspects of the cases with bladder cancer. In addition, an attempt will be made at establishing nonrandom karyotypic changes in bladder cancer and their possible relationship to causation, as extrapolated from cytogenetic studies to be done in collaboration with other laboratories, in which the karyotypic changes will be related to specific chemical inducing agents of bladder cancer in the rat. In those cancers in which a small number of cells and even a smaller number of dividing cells is availabe, an attempt will be made to differentiate normal urothelial cells from malignant ones, particularly in bladder lesions of the in situ variety and small papillary noninvasive lesions. Such studies could be performed on either small tissue speciments and/or bladder washings. One of the ultimate aims of the study is to define bladder cancer in terms of the cytogenetic abnormalities, with the hope that certain nonrandom changes may not only characterize clinical subgroups, but also be related to specific causation.